Thermoset composite material and structural component and method of making the same from engineered recycled rubber powder

Abstract

A thermoset composite material that my used in the fabrication of structural components including railroad ties comprise a substantially homogeneous blend of an amount of vulcanized rubber particles including a predetermined ratio of different particles sizes, and a thermoset elastomeric binding agent added to the vulcanized rubber particles. The blend may comprise about 30% to about 97% by weight of the vulcanized rubber particles, and the blend is subjected to compression molding at a predetermined temperature and pressure for a resident time period forming the composite material. The ratio of different rubber particle sizes is selected so that the composite material has a desired density or is within a range of desired densities.

What is claimed is: 
     
       1. A thermoset composite material, comprising:
 a substantially homogeneous blend of an amount of vulcanized recycled rubber particles including a predetermined ratio of different particles sizes, and a thermoset elastomeric polyurea binding agent added to the vulcanized rubber particles; and, 
 a fibrous filler material and a granulated silica filler material; 
 the blend comprises about 30% to about 97% by weight of the vulcanized recycled rubber particles, and the blend is subjected to compression molding at a predetermined temperature and pressure for a resident time period forming the composite material; and, 
 wherein the ratio of different rubber particle sizes is selected so that the composite material has a desired density or is within a range of desired densities. 
 
     
     
       2. The composite material of  claim 1 , wherein the blend comprises about 30% to 70% by weight of the vulcanized rubber particles. 
     
     
       3. The composite material of  claim 2 , wherein the blend comprises about 40% to 50% by weight of the vulcanized rubber particles. 
     
     
       4. The composite material of  claim 1 , wherein the blend further comprises a depolymerized vulcanized rubber material and/or an amorphous carbon material. 
     
     
       5. The composite material of  claim 1 , wherein the blend comprises about 3% to about 15% by weight of the binding agent and the remainder being the vulcanized rubber particles. 
     
     
       6. The composition material of  claim 5 , wherein the blend comprises about 5% to about 10% by weight of the thermoplastic elastomer and the remainder being the vulcanized rubber particles. 
     
     
       7. The composite material of  claim 1 , wherein the blend is subjected to compression molding at about 1,000 psi to about 5,000 psi, at a temperature ranging from about 200° F. to about 350° F. for a resident time of about 3 to 10 minutes. 
     
     
       8. The composite material of  claim 7 , wherein the blend is subjected to compression molding at about 4,500 psi, at a temperature of about 350° F. for a resident time of about 7 to 10 minutes. 
     
     
       9. The composite material of  claim 1 , wherein a particle size of the vulcanized rubber particles is about 20 mesh to about 60 mesh. 
     
     
       10. The composite material of  claim 9 , wherein the particle size of the vulcanized rubber powder is about 30 mesh to about 40 mesh. 
     
     
       11. The composite material of  claim 1 , wherein the composite material as a density from about 45 lb/ft 3  to about 80 lb/ft 3 . 
     
     
       12. The composite material of  claim 11 , wherein the composite material has a density from about 60 lb/ft 3  to about 70 lb/ft 3 . 
     
     
       13. The composite material of  claim 1 , wherein the compression molding of the blend is performed to fabricate a railroad tie. 
     
     
       14. The composite material of  claim 1 , wherein the ratio of different vulcanized rubber particles includes about 25% of −20 mesh, about 25% of −40 to +60 mesh and about 50% of −80 mesh. 
     
     
       15. A thermoset composite material, comprising:
 a substantially homogeneous blend of an amount of vulcanized recycled rubber particles produced from comminuting a rubber article at temperatures that do not exceed a glass transition temperature of the rubber article, and a thermoset elastomeric polyurea binding agent added to the vulcanized rubber particles; and 
 a fibrous filler material and a granulated silica filler material; 
 wherein the blend comprises about 30% to about 97% by weight of the vulcanized recycled rubber particles and a particle size of the rubber particles does not exceed 20 mesh; and, 
 the blend is subjected to compression molding at a pressure of at least 1,000 psi and at a temperature of at least 200° F. for a resident time period forming the composite material. 
 
     
     
       16. The composite material of  claim 14 , wherein the blend is subjected to compression molding at a pressure of about 4,500 psi at a temperature of about 350° F. 
     
     
       17. A method of making a thermoset composite material according to  claim 1 , comprising:
 mixing an amount of vulcanized recycled rubber particles, including a predetermined ratio of different particle sizes, with a thermoset elastomeric polyurea binding agent to generate a substantially, homogeneous blend; 
 providing to the blend a fibrous filler material and a granulated silica filler material; and, 
 applying a compressive molding force to the blend at a predetermined temperature and pressure for a resident time. 
 
     
     
       18. The method of  claim 17  wherein the ratio of different particle sizes includes about 25% of −20 mesh, about 25% of −40 to +60 mesh and about 50% of −80 mesh. 
     
     
       19. A railroad tie fabricated from a thermoset composite material according to  claim 1 , comprising:
 a substantially homogeneous blend of an amount of vulcanized recycled rubber particles including a predetermined ratio of different particle sizes, and a thermoset elastomeric polyurea binding agent added to the vulcanized rubber particles; and, 
 a fibrous filler material and a granulated silica filler material; 
 the blend comprises about 30% to about 97% by weight of the vulcanized recycled rubber particles, and the blend is subjected to compression molding at a predetermined temperature of about 350° F. and pressure of about 4,5000 psi for a resident time period forming the composite material; and, 
 wherein the ratio of different rubber particle sizes is selected so that the composite material has a desired density of about 60 lbs/ft 3  to about 70 lbs/ft 3 . 
 
     
     
       20. The railroad tie of  claim 19 , further comprising an elongated configuration including a top and bottom parallel surface and two parallel side surfaces wherein grooves are formed in the one or both of the side surfaces and the bottom surface. 
     
     
       21. A thermoset composite material, comprising:
 a substantially homogeneous blend of an amount of vulcanized recycled rubber particles including a predetermined ratio of different particles sizes, and a thermoset elastomeric polyurea binding agent added to the vulcanized rubber particles; and, 
 a fibrous filler material and a granulated silica filler material; 
 the blend comprises about 30% to about 97% by weight of the vulcanized recycled rubber particles, and the blend is subjected to compression molding at a predetermined temperature and pressure for a resident time period forming the composite material.